But this car-like contraption was conceived as a special effect for Renaissance festivals. It would have worked like a child's spring propelled toy, with the springs wound up by rotating the wheels.

Da Vinci probably envisaged someone hiding behind a curtain who would pull the string to release the brake.

For centuries scholars puzzled over the drawing. Several attempts were made to recreate the vehicle, but none worked.

"Everybody thought that Leonardo powered the car with the two big leaf springs shown in his sketch. Instead, the power is provided by coiled springs inside the tambours," Galluzzi said.

The new interpretation came from Professor Carlo Pedretti, director of the Armand Hammer Center for Leonardo Studies in Los Angeles, who noticed a kind of squiggle in the sketch eventually identified as coiled springs.

With the help of U.S. robotics expert Mark Rosheim, the museum first created a digital model, then a fully functioning model.

The model showed that the programmable steering mechanism, consisting of wooden blocks arranged between gears, allows the spring-propelled vehicle to go straight, or turn at pre-set angles, but only to the right.

"The model has revealed a wonderful complexity that now is very clear," Pedretti said. "Looking at it carefully, it does resemble the Spirit space vehicle used on Mars."